Bolted Steel Connections with 3-D Jacket plates and Tension Rods

ABSTRACT

This new versatile steel connection has three unique features: (1) utilizes three dimensional connection plates in a simple and consistent manner, and is suitable for all possible connection type that is made of steel W-sections; (2) uses through the depth steel rods, coupled with typical web stiffeners to transfer shear and bending moment across the connection. The shear transfer mechanism is similar to stirrups in reinforced concrete beams; (3) all components and parts can be prefabricated in shop, and conveniently bolted together at field. The merits of the connections include higher strength and ductility, stronger yet simpler connections, higher quality, small components for easy storage and transportation. In one word, it eliminates all of the inherent drawbacks and problems of conventional bolted and/or welded connections.

A completely new type of structural steel connection is invented. It is the jacket-plate-connection system using 3-dimensional connection plates and tension rods to achieve exceptional structural performance that is superior to any conventional connections, either bolted or welded, that use 2-dimensial (i.e. flat) gusset plate and/or side plates. The merits of the novel connections include higher strength and ductility, stronger yet simpler connections, higher quality, small components for easy storage and transportation. Additionally, they eliminate all of the inherent drawbacks and problems of conventional bolted and/or welded connections. The present invention is a versatile connections system that can be use in any steel frames and trusses that is made of W-sections. It basically redefines concept of structural steel connections, and has the potential to reform the current market of steel construction. The economical and social impact will be significant.

There are three very unique features of this connection system: (1) For the first time in the industry, this invention introduces three dimensional connection plates in a systematical way. It addresses all possible connection type in a simple and consistent manner. (2) This invention uses through the depth steel rods, coupled with typical web stiffeners to transfer shear and bending moment across the connection. This type of shear transfer mechanism is similar to stirrups in reinforced concrete beams and columns. Although being widely used in reinforced concrete structures for many years, it is first time that the mechanism being ever utilized in steel frames and trusses; (3) all components and parts can be prefabricated in shop, and conveniently bolted together at field. With this invention, it becomes practical to build all steel frames without field welding, including the following popular high performance seismic steel frames: special moment resisting frame (SMRF), eccentrically braced frame (EBF), and special concentrically braced frames (SCBF). (Note that there are no all-bolted SMRF, EBF and SCBR at the current market, due to the fact that traditional bolted connections cannot achieve the required strengthen and ductility at practical costs. In other words, these connections are all or partially welded connections.)

LIST OF FIGURES

Index Sketch 1: Typical steel frames that are used in building structures

-   -   (a) Special moment frames (SMF);     -   (b) Eccentrically braced frames (EBF);     -   (c) Special concentrically braced frame (SCBF)—Inverted V Type;     -   (d) SCBF—Typical Type;     -   (e) SCBF—X Type.

Index Sketch 2: Typical steel trusses that are used in bridges and infrastructures

-   -   (a) Vierendeel truss;     -   (b) Typical steel bridge truss;     -   (c) Steel truss—N brace;     -   (d) Steel truss—V Type.

FIG. 1: Moment connection at top floor—corner condition

-   -   (a) Assembly view;     -   (b) Components view.

FIG. 2: Moment connection at intermediate floor—side condition

-   -   (a) Assembly view;     -   (b) Components view.

FIG. 3: Moment connection at top floor—interior bay condition

-   -   (a) Assembly view;     -   (b) Components view.

FIG. 4: Moment connection at intermediate floor—interior bay condition

-   -   (a) Assembly view;     -   (b) Components view.

FIG. 5: Eccentrically braced frames—brace and link beam details

-   -   (a) Assembly top view;     -   (b) Components top view;     -   (c) Assembly bottom view;     -   (d) Components bottom view.

FIG. 6: Special concentrically braced frame (SCBF)—Inverted V details

-   -   (a) Assembly top view;     -   (b) Components top view;     -   (c) Assembly bottom view;     -   (d) Components bottom view.

FIG. 7: EBF and Inverted V SCBF—typical brace and beam to column connection details

-   -   (a) Assembly top view;     -   (b) Components top view;     -   (c) Assembly bottom view;     -   (d) Components bottom view.

FIG. 8: EBF and Inverted V SCBF—brace and column connection detail at foundation

-   -   (a) Assembly top view;     -   (b) Components top view;     -   (c) Assembly bottom view;     -   (d) Components bottom view.

FIG. 9: SCBF—brace and beam to column connection detail at typical floor

-   -   (a) Assembly top view;     -   (b) Components top view;     -   (c) Assembly bottom view;     -   (d) Components bottom view.

FIG. 10: SCBF—brace and beam to column connection detail at top floor

-   -   (a) Assembly top view;     -   (b) Exposed top view with front jacket plate removed;     -   (c) Components top view;     -   (d) Assembly bottom view;     -   (e) Exposed bottom view with front jacket plate removed;     -   (f) Components bottom view.

FIG. 11: SCBF—brace and beam crossing connection typical detail

-   -   (a) Assembly top view;     -   (b) Components top view.

FIG. 12: SCBF—brace crossing connection typical detail—without beam condition

-   -   (a) Assembly view;     -   (b) Exposed view with front jacket plate removed;     -   (c) Components view.

FIG. 13: Vierendeel truss—typical connection condition

-   -   (a) Assembly view;     -   (b) Exposed view with front jacket plate removed;     -   (c) Components view.

FIG. 14: Typical steel bridge truss segment

-   -   (a) Assembly view;     -   (b) Exposed view with front jacket plate removed. 

1. Three dimensional jacket plates, comprising (a) A flat side plate that cut into the shape of side projection of the joint; (b) Pairs of clamping plates welded at the perimeter of side plate with pre-drilled bolt holes. Note that clamping plates are always perpendicular to the side plate.
 2. Steel connections, made of the 3-D jacket plates as recited in claim 1, comprising a) A pair of symmetrical jacket plates, installed from opposite side of the frame or truss plane; (b) Shear transferring tension rods coupled with typical web stiffeners; Note that the tension rod, always in a plane parallel to the side plate, is full depth flange-to-flange threaded rods with bolts at each ends; (c) These are primary bolted connections, but optional field welding is allowed when additional strength is needed. (d) Conventional bolts and shear tags, gusset plates can be used in combination with jacket plates, as far as they are not interfere the jacket plates.
 3. Buding frames that is connected together using all or part of the jacket-plate-connections as recited in claim 2, including but not limited to the followings: (a) Ordinary moment frames (OMF) and special moment frames (SMF); (b) Eccentrically braced frames (EBF); (c) Ordinary concentrically braced frame (OCBF) and Special concentrically braced frame (SCBF), including but not limited to, inverted V type, X type, any typical type; (d) Other steel frame that is a variation and/or combination of the above listed ones.
 4. Steel trusses that is connected together using all or part of the jacket-plate-connections as recited in claim 2, including but not limited to the followings: (a) Vierendeel truss; (b) Typical steel bridge truss; (c) Steel truss—N brace; (d) Other steel trusses that is a variation and/or combination of the above listed ones. 